Pizzas have to stay in motion to taste good. That’s why you toss pizza dough in the air when you’re making it. If they’re stationary for too long, they stop tasting good, which is why the third slice is never as good as the first. You can trick pizza into being tasty again by putting it in the fridge–the coldness dulls its senses and makes it thinks it’s moving.

Son, I hate to break it to you, but… you’re dying. Because of the nuclear bombs that were set off during World War II, since then everyone has been mutated so that they die every night. That’s why you get tired at night.

Scientists scrambled to find a way to stop the mutation, but anything they did to heal the damage done to the body ultimately killed the brain, so the best thing they could come up with was to remove the brain every night so the body could heal.

Now, your mother and I can’t remove your brain ourselves – we’re getting our own brains removed. It’s the same for everyone else, too. So, to make sure your brain is removed while your body is healed, we’ve programmed robots to do it for us. The only problem is, they aren’t designed to look for you – they have to be programmed where you are. Because of this, they’re programmed to look for you in bed, and when you go on trips, we have to reprogram them to your new location (that’s why it’s always such a hassle for us when you have a sleepover).

Back when dogs were first starting to be born, the Earth was entirely still. The dogs didn’t like having to travel all the way to the other side of the Earth to get some sleep, so they all started to spin around when they wanted to rest. Since they all did it at the same time, the Earth spun and the sun went down. Thanks to momentum, they don’t have to do it anymore, but they do out of tradition and habit.

The best answers are obviously “unified theories” that explain a few other details along the way. And that reveals Bill Watterson’s genius: He used Calvin’s dad as a satire of Aristotle or other great thinkers who didn’t bother scientifically testing their theories.